Green Materials Report – Smog Eating Roof Tiles

September 16, 2014

This post is part of the green materials report series. GBE is providing information on various building materials and what makes them green. Each post focuses on one material. We will be looking at the ingredients in the material, how it is used, what makes green materials green, and any green product certifications that it has earned. We hope to develop a database of information to help consumers make informed choices about what goes in their buildings.

A team of students at the University of California – Riverside have devised a way to create roof tiles that actively destroy smog. Scientists tell us that smog is caused primarily by sunlight interacting with the nitrogen oxide gas emitted by vehicles and electric generating stations. Titanium dioxide reacts with nitrogen oxide, converting it into less reactive compounds.

The secret is to spray a coating of titanium dioxide on the clay roofing tiles so popular in southern California. When the tiles are installed, they break down 88 – 97% of the nitrogen oxide smog and air pollution that they come in contact with into non-photo reactive elements, thereby reducing the formation of smog. One roof coated with titanium dioxide could offset the nitrogen oxide emitted by driving a gasoline powered car 11,000 miles. The best part is that the titanium dioxide used in these air-scrubbing roof tiles is both plentiful andcheap! The students who developed the tiles estimate that coating all the tiles needed for a typical suburban roof would add just a few dollars to the total cost of materials.

The UC students’ work has already won them a $15,000 prize from the EPA – but they aren’t done yet. They want to take their smog-beating research further and add a titanium dioxide coating to exterior paint, concrete and even highway dividers. That’s changing the world!